One Piece Floor Pan install

I am considering buying a one piece floorpan for my 70 FM3 Duster 340 project. Before I pull the trigger, how much of a pain in the *** is it to get that sucker inside the vehicle? How do you do it? Through the windshield area? Or do you have to remove the quarter windows?

My center hump is fine but I like the idea of not having non-factory seams from fitting the two halves instead.